Device for controlling the adjustment and operative actuation of impulse contacts in telephone dials



April 11, 1950 J. E. BOSH 2,503,541

' DEVICE FOR CONTROLLING THE ADJUSTMENT AND OPERATIVE I ACTUATION 0F IMPULSE CONTACTS IN TELEPHONE DIALS Filed Aug. 6. 1947 INVENTOR:

' JAMES E. BOSH ATTORNEY UNITED STATES PATENT OFFICE DEVICE FOR CONTROLLING THE ADJUST- MENT AND OPERATIVE ACTUATION OF IMPULSE CONTACTS IN TELEPHONE DIALS James E. Bosh,-Berwyn, Ill., asslgnor to Kellogg Switchboard and Supply Company, Chicago, 7 Ill.,acorporation of Illinois Application August 6, 194%, Serial No. 766,852

4 Claims. (01. 17990) This invention relates to dial calling devices, such as are used in subscribers stations in autoinatic telephone systems, comprising a finger dial which may berotated from a normal to a desired numerical position from which it returns to normal to generate impulses, and is particularly concerned with novel means for controlling the adjustment and the operative actuation of the impulse contact springs.

finger dial, thereby saving wear and tear on the governor at the expense of added mechanical elements to which the wear and tear is transferred.

The general and principal object of the invention is to provide a dial calling device having simplified means for obtaining the operative actuation of the impulse cam under control of the governor to determine the operative actuation of Dial calling devices of the type indicated above the impulse contact springs and providing simpliare provided with a pair of coacting impulse confi d adjus i m n ss i d W the mp tact springs arranged for operation by an actucontact springs which coact cooperatively to do ating element which may be a radially lobed imtermine the gap between the contact points and pulse cam associated with a cam shaft geared to the dwell of the lobes of the impulse cam rotate with the finger dial during the return ro- The invention proposes, in accordance with one tation thereof to normal from any numerical 100- of its specific objects, to eliminate the special sition to which it may havebeen advanced. The backing and adjusting member associated With desired series of impulses is generated by sucthe impulse contact springs of prior structures cessive operative actuation of the impulse conand to provide, instead, individually adjustable tact springs by the radial lobes of the rotating forked impulse contact springs forming a pair of impulse cam. The speed of return rotation of individually adjustable coacting extensions or the finger dial, and therewith of the impulse cam, legs carrying the contact points, and also formis regulated by a governor carried on a rotatable ing a pair of individually adjustable coacting exshaft provided with a worm gear which is actutensions or legs constituting operating members ated by a toothed drive wheel geared to rotate for operative coaction with the radial lobes of with the finger dial. the impulse cam, thus reducing the cost and facil- It is necessary in such dial calling devices to itating adjustments.

provide for a .correct gap between the contact Another object of the invention is to provide points of the impulse springs, when the springs a novel worm drive wheel coacting with the cam ere'in p or s p d nditi n, and to p sishaft in one-way free-wheeling engagement tion the springs properly with respect to the imtherewith, and means for clutching said worm pulse cam so as to obtain the correct dwell of drive wheel with said cam shaft to rotate therethe cam and therewith the desired percentage with only during the return rotation of the finger ratio between open and closed contact condition dial. Separate control means such as pawl and incident to the operative actuation of the im' ratchet means, employed in prior structures for pulse springs by the impulse cam. Prior struckeepin the worm drive wheel at rest during the tures provide for this purpose a special backing forward setting rotation of the dial, are in this or adjusting member associated with the impulse manner likewise eliminated. springs for adjusting one spring relative to the Still another object is to provide a new Worm other and the position of both springs relative to 40 drive wheel carrying teeth forming angular surthe impulse cam. Displacement of the backing faces which engage theconvolutions of the worm member afiects both impulse springs as a unit, gear, during the forward rotation of the finger thus limiting the adjustment possibilities. dial to a desired numerical position, to exert a It is also desirable to keep the governor at rest lateral blocking pressure thereon in a direction during the setting or forward rotation of the extending radially at an angle to the axis of the finger dial and to cause its operative actuation Worm gear shaft, whereby the worm drive wheel only during the return rotation of the finger dial is held against rotation with the cam shaft, thus when the braking function of the governor is preventing the operative actuation of the worm needed to regulate the speed of rotation of the gear and therewith operation. of the governor. impulse cam, thus saving wear and tear on the Each tooth of the drive wheel forms a' generally governor. Prior structures employ for this purradially extending drive surface for driving enpose awl and ratchet means for causing operagagement with the convolutions of the worm gear, tively, veifective rotation of the worm drive wheel during the return rotation of the finger dial when to actuate the worm gear and therewith the govthe drive wheel is clutched to rotate with the cam erno'r: only incident to the returnrotation of the shaft, to exert pressure on the worm gear, which is effective in a direction extending substantially in parallel with its axis, causing operatively effective rotation of the governor to regulate the speed of the return rotation, thereby controlling the correct successive operative actuation of the impulse contact springs by the impulse cam associated with the cam shaft.

The objects and features intimated in the foregoing, and additional objects and features, will appear from the detailed description of an embodiment which is rendered below with reference to the accompanying drawings. In these drawings,

Fig. 1 is a front elevational view of an embodiment of the dial callin device in which the im provements forming the subject-matter of the invention are incorporated;

Fig. 2 shows an elevational rear view of the device with some parts broken away and in section, respectively, to indicate details;

. Fig. 3 illustrates a sectional. view taken approximately along lines 3-3 in Fig. 2 to show the relative position of someof the essential elements of the structure, the finger dial being, omitted;

Fig. 4 is an enlarged diagrammatic view of the new impulse contact springs as seen from the rightin Fig. 2;

Fig. 5 is an enlarged diagrammatic view showing portions of the governor shaft with its associated worm gear partially in section and fractions of the worm drive wheel illustrating how its teeth coact with the. worm gear incident to the operatively effective return rotation of the finger dial; and

Fig. 6 shows a diagrammatic view analogous toFig. 5, illustrating the blocking coaction of the teeth. of the worm drive wheelv with the worm gear during the forward rotation of the finger dial to a desired numerical position.

Like parts are numbered alike throughout the drawings. Known details and elements will be discussed only to the extent required for an understanding of the invention.

The improvements formingv the subject-matter of the present invention may be incorporated in a dial calling device such as disclosed, for example, in the co-pending application Ser. No. 738,646, filed April 1, 19.47.

The new impulse contact springs 9 and ID are mounted in a pile or stack together with off-normal contact springs on a lateral extension. I l pro..- jecting from an. angular mounting bracket I2 having legs |3--l4 secured to the' flange l5 of a cup-shaped housing having the recessed portion [8. The off-normal contactsprings are indicated in Fig. 3 underneath the impulse contact springs 9 and Ill but are not marked. by reference numerals. Lugs l'l-20' are provided for mounting the dial device on a suitable support. Disposed in front of the device is the rotatable'finger dial 2| and the finger stop 22. Therfinger dial is keyed. to a main shaft 23 (see Fig. 3) which is journalled in the wall [6 of the cup-shaped housing, its free end being, journalled. in a suitable bearing in the mounting bracket. l2. The main shaft 23 carries a gear wheel 24 which meshes with a pinion 25 associated with the cam shaft 26,v

and the latter is. rotatably suitably journalled at one. end in the wall I B'of the cup-shaped housing and at the other end in the mountingbracket l2. Secured to thegear wheel 24 is the stop cam plate 2T. This. plate carries an arm (not visible in Fig. 3) radially projecting therefrom beyond the gear wheel 24 for engagement, in normal positionof the device, with a stop member which projects radially inwardly from the wall of the housing, and also carries a cam projection 28 for coaction with an insulating member 29 secured to an ear 3| projecting from one of the ofi-normal springs. The off-normal springs are actuated to mark the off -normal position when the finger dial is rotated in forward direction, rotating the stop cam plate and thereby displacing the cam projection 28 with respect to the member 29, allowing this member to drop and thus placing the off-normal contacts into alternate operative position. The function of the offnormal springs is known and need not be further discussed. Associated with the main shaft 23 is a coiledspring (not shown) one end of whichis anchored in the mounting bracket I2 by means of the fastening device 30 and the other end of which is anchored in the stop cam plate 21. Accordingly, when the finger dial 2| is rotated in forward clockwise setting direction, as seen v in Fig. 1, the shaft 23 will be rotated and will rotate the gear wheel'24, thereby winding its associated coiled spring, storing power which is utilizedin well known manner for rotating the finger dial to normal home position.

Each of the new impulse springs 9 and i0 is forked at its free end, as particularly shown in Fig. 2.. The spring 9'forms in this manner a longitudinal arm or extension 31 which carries an impulse contact point 38 and a longitudinal. extension or arm 39 which is. ofiset transversely inwardly, as particularly shown in Fig. 4, forming a camming, or operating. member for coaction with the impulse cam. The spring in forms in like manner an extension or arm 40 carrying, an

. impulse contact point. such as 38, for coaction with the contact point projecting from the arm or extension 31, and a transversely inwardly offset arm or extension 4| forming. a camming or operating member for camming coaction with the operating member 39. Each spring 9-|0 is individually adjustable and each longitudinal exten sion or arm projecting therefrom is likewise individually adjustable. The contact springs proper formed by the extensions. or arms 31 and 40, which carry the contact points such as 38, can thus be individually adjusted relative to. each other, and the coacting. camming or operating arms or members 39 and 41 can be individually independently adjusted to determine their mutual coaction and their positional relationship relative to the contact-carrying extensions 31 and 40. Thepair of coacting operating or camming arms 39 and 4|, as well as the pair'of coacting contact-carrying extensions 3.! and 40, are thus integral with their respective contact springs 9| II.

The pinion 25 is integral with or keyed to the cam shaft 26 and is'provided with a hub axially extending therefrom to which is secured the coiled spring 45. The new worm drive wheel 46, which may be made of suitable'material, is provided'with a disklike member 41 carrying a short hub which extends axially toward the pinion 25 and is frictionally engaged. by the convolutions of the coiled spring 45 at the free end thereof. The arrangement operates in the manner of a free-wheeling one-way clutch which clutches the new worm drive wheel 46 with the cam shaft 26 or, rather to say, with the pinion 25, only during thev operatively effective return rotation of the finger dial 2| to normal from: any numerical position to which the dial may have been advanced. The. coaction is such that the. convolutions of the coiled spring 45 are tightened radially around the hub of the disk" secured toth'e'worm drive 7 wheel 46, during the return rotation of the finger dial, while such convolutions are effected in reverse direction, tending to open radially'around the hub when the dial is rotated in setting or forward direction. It will be observed, however. that during such forward setting rotation of the finger dial a slight torsional force is applied to the worm drive wheel 46 by slight frictional engagement of the clutch spring 45 with the hub of the d ive wheel tending to rotate the drive wheel.

The governor comprises the shaft 48 carrying a worm 49. The worm is formed by a coiled wire disposed in spiral grooves cut on the governor shaft 48; that is, the wire forming the worm is disposed on the shaft in the manner of a thread, as indicated particularly in Figs. 5 and 6. The governor shaft is rotatably journalled at one end in a bearing 56 secured to the ear 5! projecting laterally from the mounting bracket 12, and at the other end in a bearing recess provided in the governor cup 52 which is secured to an ear 53 projecting laterally from the mounting bracket 12 at the opposite end thereof. Weighted resilient members 54 are provided on the governor shaft, and when the shaft is rotated the free ends of these members are forced radially outwardly and exert a braking force on the inside of the cup 52, thereby regulating the speed of the return rotation of the finger dial and parts actuated thereby.

It will be seen from the foregoing description of the governor that the sides of the worm 49, being formed of a wire, are identical. A substantially identical driving force applied to either side of the worm would therefore cause rotation of the worm shaft, that is, of the governor, and such rotation would result during rotation of the finger dial in either direction. The rotation of the governor during the forward setting rotation of the finger dial is undesirable because it would cause additional wear and thus shorten the life of the device. In order to avoid such undesired governor action, the teeth of the new worm drive wheel 46 are cut so as to form angularly extending surfaces 55 for engagement with the convolutions of the worm 49 during the initial forward setting rotation of the finger dial 2|, when the pinion 25 and therewith the clutch spring 45 and the cam shaft 26 are rotated in clockwise direc tion, as seen in Figs. 2 and 6. As mentioned before, the slight frictional engagement of the clutch spring 45 with the hub of the disk 41, during the forward setting rotation of the dial, tends to rotate the Worm drive wheel 46. The angle of the surfaces 55 of the teeth is such that, when the slight frictional force attempts to rotate the worm drive wheel, these surfaces press against the convolutions of the worm from the side, radially and angularly inwardly, as indicated by arrows in Fig. 6, thus exerting an angular lateral thrust which tends to wedge the worm gear shaft in its bearings, diagrammatically indicated at 50 and 52, thereby opposing the slight frictional torsion force of the clutch spring 45. This force therefore is without effect, and the toothed drive wheel 46 and, with it, the governor remain at rest. The pinion 25 and, with it, the cam shaft rotate in free-wheeling operation with respect to the worm drive wheel with its teeth in engagement with the worm gear, as shown in Fig. 6.-- This condition persists throughout the forward rotation of the finger dial until it has been operated to the desired numerical position.

The pinion 25 and with it the camshaft 26 retate in free-wheeling operation with; respect to the worm drive wheel which remains at rest, with its teeth in engagement with the worm gear, as

shown in Fig. 6. This condition persists throughout the forward rotation of the finger dial until it has been operated to the desired numerical position.

The clutch device, including the coiled spring 45, becomes operatively effective during the return rotation of the dial, when the braking and speed-regulating action of the governor is required. At the inception of the counter-clockwise rotation of the finger dial and therewith of the pinion 25, the new worm drive wheel 46 will initially tend to rotate in counter-clockwise direction by frictional tension transmitted thereto by the spring 45, and the radially extending surfaces 62 of its teeth will engage the convolutions 49 of the worm gear, as shown in Fig. 5, exerting pressure thereon which is effective in a plane generally paralleling the axis of the governor shaft 48. The engagement of the driving surfaces 62 of the teeth of the worm drive Wheel with the convolutions of the Worm gear, as shown, supports the frictional force of the clutch. spring 45, causing such spring to tighten radially around the hub extending from the worm drive wheel 46,

thereby positively clutching the drive Wheel with the pinion 25 and rotating it coincident with the counter-clockwise rotation of the cam shaft 26 to rotate the worm gear shaft and therewith the weighted members 54. The governor is thus operatively effective to regulate the speed of the return rotation of the finger dial and therewith the speed of the cam shaft 26.

Associated with the cam shaft 26 is the nonmetallic impulse cam 65 carrying a number of radial lobes, as shown in Fig. 2. The impulse cam carries an arcuate resilient spring pawl at its under side for driving engagement with a ratchet plate keyed to the cam shaft, to rotate with the cam shaft when such shaft is rotated-in counter-clockwise direction coincident with the return rotation of the finger dial. On its upper side the impulse cam 65 carries a similar arcuate resilient pawl spring 66, shown in Fig. 2, which coacts, in the nature of a detent, with apertures provided in the corresponding overlying portion of the mounting member 12.

Thelobes of the impulse cam 65. uponoperatively effective rotation thereof, pass in counter-clockwise direction as seen in Fig. 2, through the transversely inwardly offset extensions or arms forming the pair of coacting camming or operating members 39 and 4| of the impulse springs 9 and H1, thus successively forcibly spreading these operating members and again returning them to normal. The pair of coacting extensions 3'! and 40, carrying the impulse contact points such as 38, are thereby likewise successively spread apart and returned to normal, thus successively opening andclosing the impulse contact points and generating the desired series of impulses in accordance with the initial numerical setting of the finger dial.

The initial adjustment of the pair of coacting operating arms or members 39 and 4| and of the pair of coacting contact-carrying extensions 31 and 40 is such as to produce a desired correct gap between the contact points when the contact springs are in spread-apart or open position. This gap and the dwell of the actuating lobes of the impulse cam determine the relative percentage ratio between open and closed contact condition incident to each operative actuation of the contact springs. For example, a given gap between the contact points in open position of the impulse -springs may: produce 7 a 1 percentage ;ratio: of '38.5%.:and 6l.5%; that is, intealch' opeerativeeactuation of" the impulse :contactrsprings thercontact points willtbejclosed 38.5% and open 61.5% of the time. It will be understoodthat, ziifi the gap between the contactxpoints' 'is'xchanged, -such ipercentage. ratio will likewise 'be afiected. TiFortexample, if the-gap is. increased; thexdwell of they lobesrofxthe impulse :cam is correspondingly increased, the time of: contact closure is shortened,

iandrthe time whenithe contacts ;are separated is lengthened. The initially-adjusted :gap may be echanged r by c the .wear: and tear on the contact :points; increasing 1 the "gap, or by 'therwear :and

'zteargonthelobes of-the'impulse cam ;or;on the 1 ccammingrsurfaces-of the "pair of:coacting operatingrorcamming members 39 and-4 l.

. :Ifanthe initially-adjusted correct igap between :the; contact points is, changed; dueto any: cause,

:which may be establishedcbyproper testsgat-the cexchange, the "required adjustment ;may :be -.quickly-and effectively-restored either bycorxrecting the --;angle of the contact-carrying exptensions 31 and r40 -or .by correspondingly correcting the angleeat which thewinwardly ofiset the invention-contributes toward facilitating man- .ufacture byeliminating; parts, thereby .decreasing the-cost of the unitproduct, and at theisame time lengthening its usefullifetand facilitating adjustments that'may beJrequired.

'Certain-features of the invention may be use-..

'ful indevicesother than calling dials, and-modifications may be made. Itwill therefore be understood that a specific example has been "dislclosed for illustrative; purposes :only, and that changes may be made within the scope andrspirit;

:of theappended claims.

.IcIaim:

1. .ln a dial calling device. havingsa finger-dial which may be rotated froma normal toa desired z'numerical position from whichsit returns to nor-;;

.mal to generate impulses and; having a governor carrying awormsformedby a wirehaving. iden- ':.tical,sides,-a shaft geared for rotation with said finger dial and carrying a toothed -wormdrive wheel for; driving said" worm, the teeth of; said *worm drive wheelbeing beveled toexert :a lateral thrust upon the-convolutions of :said wormt'during rotation of said shaft which correspondsz'to vforward setting-rotation'ofrsaid fingerrdial so as rtozlock said worm against rotation and toyin- -hibit thereby rotation -:of said governor wduring suchiforward setting-rotation ofsaid finger: dial, tend-clutch means; eifective' during the' return-roctation of the finger cdial: for positively 1 clutching said- Worm drive wheel with said shaftto'efl'ect' rotation-thereof-so as to rotatesaid worm'torop-tatesaidiagovernor.

:2.JIn:=a'-ca11ing :device :of the :class "described uhavingta "finger 'tdial which imayxbe': rotated r'forlnwardlyfiromza normal :to ;a .;desired' numerical ,vpositionfrom iwhich'itrotates to normal and-a governor comprising a'shaft-carrying-a worm-and including a :pinion geared for rotation with-said finger dial in eitherfidirection of rotation thereof and a toothed, drive wheel for driving said-worm, clutch means disposed between said pinionand said toothed 'drive wheel for positively 'rotating .said toothed: drive wheel to drive said worm;responsive to rotation of said pinion during the return :rotation of said dial, said clutch means ,exerting-ia-slight torsional force on said" toothed :drivewheel responsive to rotation of said pinion :during the forward rotation of said fingerdial 1to=a desirednumerical position which attempts :to' rotate: such. drive wheel, the teeth of said-drive uwheelv forming angularly extending surfaces' for engagement with the convolutions of said worm on one-side thereof. incident to. rotation ofrsaid pinion-responsive. to the forward rotationofi-said finger dial, toexerta lateral thrust on saidworm which looks it against rotation to inhibit rotation of said governor during such forward -rotation of said: finger dial. I 3. In a-calling device of the class describe having a-finger dial whichnmay be rotated forwardly from a normal to a desired; numerical position .from which it' returns to ;normal=and :a

governor "comprisinga shaft carrying a worm having convolutions forming identical sides-and including arpinion geared for rotation withcsaid "finger dial ingeitherdirection of rotation thereof and atoothed drive wheelior driving said worm, a clutch spring :disposed between said toothed drive wheel and said pinion and rotatablewith ,said' pinion for positively --rotating said toothed drive wheel to drive, said worm responsive to T0- tation of said'pinion during the return rotation of said finger dial,-said clutch spring exerting-a slight torsional force on said toothed drive wheel responsive to rotation of said pinion during the forward rotation of said finger dial which attempts to rotate such drive wheel, the teeth-of said dr-ive' wheel forming angularly extending surfacesforengagement with the convolutionsof said worm onlone side thereof, incident to'rotation of said pinion during the forward rotation of saidfinger dial, to exert a lateral thrust thereon which locks said worm against rotation to inhibitv rotation of said governor during such forward rotation of said finger dial.

4.11131 calling device of the class described having a finger dial which may be rotated forwardly from a normal to a desired numerical position from which it returns to normal position to generate impulses and having a pinion geared to:rotate with said finger dial in either direction of rotation'thereof and including :a

' shaft extending axially from said pinion, a

toothed'drive wheel rotatably disposed on said "shaft, "a hublike extension projecting axially from said drive wheellin the direction of said pinion, a governor having a shaft carrying a worm for driving coaction with said toothed drive wheel, a coiled clutch spring extending from said pinion-and being rotatable therewith, 'the'convolutions at the free end of saidcoiled clutch spring-'surrounding'the hublike extension of said toothed drive wheel in relatively loose frictional engagement therewith and exerting slight torsional force thereon responsive to rotation of said pinion during forward rotation of said finger dial which attempts to rotate said toothed drive "wheel while tightening-around said hublike extension'responsive to'rotation of said pinionduring return-to-normal rotation of said *finger "dial for positively rotating said toothed drive wheel to rotate said Worm so as to actuate said governor,

the teeth of said drive wheel forming angular JAMES E. BOSH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,158,951 Adams Nov' 2, 1915 1,609,982 Blessing Dec. '7, 1926 1,615,311 Obergfell Jan. 25, 1927 2,096,054 Miller Oct. 19, 1937 2,253,968 Cook Aug. 26, 1941 FOREIGN PATENTS Number Country Date 2,870 Great Britain Oct. 26, 1871 

